The genus Erebia is one of the more controversial groups among the Holarctic Lepidoptera. In this genus, composed of around 100 mountain species, the Erebia tyndarus complex has certainly been a major source of debate for more than a century. According to the literature, between 2 and 11 species, and at least 45 subspecies or semi-species have been recognized. For the first time, we provide a complete molecular study, based on the ND5 and CoxII mitochondrial gene sequences, including all the recognized species and 60% of the subspecies of the entire group, with European, Caucasian, Siberian and North-American taxa. Our analyses led us to recognize 11 species even though there was some poor discrimination between Western Europe species. A complete study of the events of speciation is presented in the light of glacial and interglacial cycles during the Pleistocene.